The US pollutes more, absolutely and per head, than any other country (it also produces more wealth). Its greenhouse emissions have risen by more than 11% since 1990: its Kyoto commitment was to reduce them by 6%. It is the only country to have signed the protocol and then to have repudiated it. President Bush said in March the US would not ratify Kyoto, because he thought it could damage the US economy and because it does not yet require developing countries to cut their emissions. His domestic and foreign critics think the US will lose economically by staying aloof.